Process of obtaining molybdenum compounds.



UNITED siaans PATENT OFFICE.

ERIC HJALMAR WESTLING AND CARL ANDERSEN, OF SAN FRANCISCO, CALIFORNIA;

SAID WESTLING ASSIGNOR OF HIS ONE HALF T0 NEWTON W. STERN, OF SAN FRAN- CISCO, CALIFORNIA.

PROCESS OF OBTAINING MOLYBDENU'M COMPOUNDS.

No Drawing;

To all whom it may concern:

Be it known that we, ERIC HJALMAR WESTLING, a citizen of the United States, and CARL ANDERSEN, a subject of Denmark, and residents of the city and county of San Francisco, State of California, have 1lointly invented a certain new and useful rocess of Obtaining Molybdenum Compounds, of which the following is a specification.

The invention relates more specifically to a. process of separating molybdenum compounds from molybdic acid solutions.

An object of the invention is to provide a process for producing substantially pure molybdic compounds.

Another object of the invention is to provide a process for separating molybdenum compounds from molybdic acid solutions.

The invention possesses other advantageous features, some of which, with the foregoing, will be set forth at length in the following description where we shall outline in full the preferred method of carrying out.

the process of our invention. It is to be understood, however, that-[variations in the process may be made without departing from the spirit of the invention as expressed in the succeeding claims.

The. first step in our process consists in precipitating molybdic acid from its solution in such a manner as to form a combination with a trivalent metal, and we prefer to use an aluminum or a ferric salt in this step. If the molybdic acid occurs as an ammonium molybdate, sodium molybdate or other alkaline or soluble molybdate, We add a ferric,

aluminum or other trivalent salt of a strong acid to the solution, such as ferric sulfate. The simplest form of the attendant reaction may'be expressed as follows: 3Na,lll[oO,-}-Fe (S0,)

any other alkaline'carbonate or hydroxid or with calcium or other alkaline earth carbonate or hydroxid. The simplest form of Specification of Letters Patent.

Patented Deo.11,1917.

Application filed October 9, 1916. Serial No. 124,506.

the attendant reaction may he expressed as follows:

If the solution does not contain at the beginning enough of the iron or other trivalent salt, it should be added thereto before neutralization takes place.

l/Ve realize that the reactions as expressed essentially by the foregoing equations and which yield essentially the same product of combination between molybdic acid and iron or other trivalent oxid, are complicated by the tendency of molybdic acid to form complex acids and salts, depending on conditions of temperature, pressure and concentration, as well as ionic concentration depending on what particular base is used, and other conditions, but we find that for all practical purposes this condition is of no material importance, as all the different combinations between molybdic acid and a trivalent base that we have examined have essentially the same useful and valuable property of being insoluble in water, and soluble without difliculty in acids and readily decomposed by bases. Also, these combinations will not take up copper or other divalent ions until the trivalent base is first satisfied. This makes it possible to effect a complete separation of molybdenum as salts of molybdic acid from copper and other ingredients, valuable in themselves, sometimes, but an impurity in molybdic products.

A salt of the approximate composition as given in the equations above containing about one molecule of ferric' oxid to three the solution in larger quantity than expressed by the ratio of one molecule of ferric oxid to three molecules of molybdic acid. It is a light brown precipitate, and contains approximately one molecule of Fe O to one molecule of M00 Whether this is merely a mixture of the yellow salt and ferric hydroxid, or a distinct chemical individual We do not yet know, but our experiments seem to indicate the latter.

The molybdenum compounds produced by the former steps are then treated to produce pure molybdenum salts. The molybdenum compounds are separated from the solutions by filtration or otherwise and then washed with water. The ferric or other trivalent molybdic compound is then digested with sodium carbonate or hydroxid or with ammonium hydroxid or other soluble base, to produce sodium molybdate, ammonium molybdate or other molybdates which may be sold in that form and utilized in the arts. This characteristic reaction may be expressed as follows:

The ferric hydroxid formed in this reaction is very readily filtered and the clear num or other trivalent hydroxids left after the last filtration. I

We claim: 1. The process of separating molybde- Copper and other divalent emons num compounds from materials containing molybdenum, which conslsts 1n precipitating molybdic acid as a molybdate of a trivaneutralizing the solution with an alkaline basic compound whereupon a molybdate of the trivalent base is recipitated.

4:. The process 0 separating molybdenum compounds from molybdate of a trivalent base, which consists in digesting the molybdate with a soluble base, whereby a molybdate of the soluble base is formed.

5. The process of separating molybdenum compounds from solutions containing molybdic acid and not much. free acid, which consists in adding a ferric salt to the solution to precipitate ferric molybdate, separating the precipitate from the solution and digesting the precipitate with a soluble base.

6. The process of separating molybdenum compounds from solutions containing molybdic acid in an acid solution, which consists in adding a trivalent base tothe solution and neutralizing the solution with an alkaline basic compound whereby a molybdate of the trivalent base is precipitated.

In testimony whereof, we have hereunto set our hands at San Francisco, California, this 25th day of September, 1916.

ERIC HJALMAR WESTLTNG. EARL ANDERSEN. Tn presence of H. G. Pnosr. 

